Active surveillance for low-risk prostate cancer: Need for intervention and survival at 10 years

Impact of a negative confirmatory biopsy on risk of disease progression among men on active surveillance for prostate cancer

OBJECTIVE

Most prostate cancer active surveillance (AS) protocols suggest a confirmatory biopsy within 12 to 18 months of diagnosis to mitigate the risk of unsampled high-grade disease. We investigate whether the results of confirmatory biopsy impact AS outcomes and could be used to tailor surveillance intensity.

METHODS

We retrospectively reviewed our institutional database of prostate cancer patients managed by AS from 1997 to 2019 who underwent confirmatory biopsy and ≥3 biopsies overall. Biopsy progression was defined as either an increase in grade group or an increase in the proportion of positive biopsy cores to >34% and was compared between patients with a negative vs positive confirmatory biopsy using the Kaplan-Meier method and Cox proportional hazards regression.

RESULTS

We identified 452 patients meeting inclusion criteria for this analysis, of whom 169 (37%) had a negative confirmatory biopsy. With a median follow-up of 6.8 years, 37% of patients progressed to treatment, most commonly due to biopsy progression. A negative confirmatory biopsy was significantly associated with biopsy progression-free survival in multivariable analysis (HR 0.54, 95% CI 0.34-0.88, P = 0.013), adjusting for known clinical and pathologic factors, including use of mpMRI prior to confirmatory biopsy. Negative confirmatory biopsy was also associated with an increased risk of adverse pathologic features at prostatectomy but not with biochemical recurrence among men who ultimately underwent definitive treatment.

CONCLUSIONS

A negative confirmatory biopsy is associated with a lower risk of biopsy progression. While the increased risk of adverse pathology at time of definitive treatment sounds a small cautionary note regarding decreasing surveillance intensity, the majority of such patients have a favorable outcome on AS.

Accurate prostate cancer detection based on enrichment and characterization of prostate cancer specific circulating tumor cells

BACKGROUND

The low specificity of serum PSA resulting in the inability to effectively differentiate prostate cancer from benign prostate conditions is a persistent clinical challenge. The low sensitivity of serum PSA results in false negatives and can miss high-grade prostate cancers. We describe a non-invasive test for detection of prostate cancer based on functional enrichment of prostate adenocarcinoma associated circulating tumor cells (PrAD-CTCs) from blood samples followed by their identification by immunostaining for pan-cytokeratins (PanCK), prostate specific membrane antigen (PSMA), alpha methyl-acyl coenzyme-A racemase (AMACR), epithelial cell adhesion molecule (EpCAM), and common leucocyte antigen (CD45).

METHODS

Analytical validation studies were performed to establish the performance characteristics of the test using VCaP prostate cancer cells spiked into healthy donor blood (HDB). The clinical performance characteristics of the test were evaluated in a case-control study with 160 known prostate cancer cases and 800 healthy males, followed by a prospective clinical study of 210 suspected cases of prostate cancer.

RESULTS

Analytical validation established analyte stability as well as acceptable performance characteristics. The test showed 100% specificity and 100% sensitivity to differentiate prostate cancer cases from healthy individuals in the case control study and 91.2% sensitivity and 100% specificity to differentiate prostate cancers from benign prostate conditions in the prospective clinical study.

CONCLUSIONS

The test accurately detects PrAD-CTCs with high sensitivity and specificity irrespective of stage, serum PSA or Gleason score, which translates into low risks of false negatives or overdiagnosis. The high accuracy of the test could offer advantages over PSA based prostate cancer detection.

A machine learning approach to predict progression on active surveillance for prostate cancer

PURPOSE

Robust prediction of progression on active surveillance (AS) for prostate cancer can allow for risk-adapted protocols. To date, models predicting progression on AS have invariably used traditional statistical approaches. We sought to evaluate whether a machine learning (ML) approach could improve prediction of progression on AS.

PATIENTS AND METHODS

We performed a retrospective cohort study of patients diagnosed with very-low or low-risk prostate cancer between 1997 and 2016 and managed with AS at our institution. In the training set, we trained a traditional logistic regression (T-LR) classifier, and alternate ML classifiers (support vector machine, random forest, a fully connected artificial neural network, and ML-LR) to predict grade-progression. We evaluated model performance in the test set. The primary performance metric was the F1 score.

RESULTS

Our cohort included 790 patients. With a median follow-up of 6.29 years, 234 developed grade-progression. In descending order, the F1 scores were: support vector machine 0.586 (95% CI 0.579 - 0.591), ML-LR 0.522 (95% CI 0.513 - 0.526), artificial neural network 0.392 (95% CI 0.379 - 0.396), random forest 0.376 (95% CI 0.364 - 0.380), and T-LR 0.182 (95% CI 0.151 - 0.185). All alternate ML models had a significantly higher F1 score than the T-LR model (all p <0.001).

CONCLUSION

In our study, ML methods significantly outperformed T-LR in predicting progression on AS for prostate cancer. While our specific models require further validation, we anticipate that a ML approach will help produce robust prediction models that will facilitate individualized risk-stratification in prostate cancer AS.

Of Screening, Stratification, and Scores

Technological innovations including risk-stratification algorithms and large databases of longitudinal population health data and genetic data are allowing us to develop a deeper understanding how individual behaviors, characteristics, and genetics are related to health risk. The clinical implementation of risk-stratified screening programmes that utilise risk scores to allocate patients into tiers of health risk is foreseeable in the future. Legal and ethical challenges associated with risk-stratified cancer care must, however, be addressed. Obtaining access to the rich health data that are required to perform risk-stratification, ensuring equitable access to risk-stratified care, ensuring that algorithms that perform risk-scoring are representative of human genetic diversity, and determining the appropriate follow-up to be provided to stratification participants to alert them to changes in their risk score are among the principal ethical and legal challenges. Accounting for the great burden that regulatory requirements could impose on access to risk-scoring technologies is another critical consideration.

Outcomes of Active Surveillance for Men With Intermediate Risk Prostate Cancer: A Population-Based Analysis

OBJECTIVE

To assesses if active surveillance (AS) is an appropriate treatment modality for patients with intermediate risk (IR) prostate cancer (PCa) utilizing population-level data to compare the survival outcomes of men with low risk (LR) and IR PCa initially treated with AS, watchful waiting (WW) or active treatment (AT).

METHODS

In total, 166,244 patients were initially identified in the surveillance, epidemiology, and end results database using biopsy Gleason grade group (GG) alone-GG1 and GG2. In total, 94,891 patients with GG1 and GG2 disease were further stratified by National Comprehensive Cancer Network risk categories-LR, favorable IR (fIR), and unfavorable IR (uIR). Predictors of cancer-specific (CSS) and overall survival (OS) were analyzed, stratified by risk classification and initial treatment-AT (first-line curative surgery or radiotherapy), AS or WW, utilizing the new "Watchful waiting recode (2010+)" variable.

RESULTS

We found GG2 patients on AS had worse CSS and OS than GG2 patients who received AT and GG1 patients treated with AS or AT; these trends persist within the National Comprehensive Cancer Network fIR and uIR cohorts. WW patients (GG1, GG2, LR, fIR, and uIR) had the worst survival outcomes of any cohort (log-rank tests P < .05).

CONCLUSIONS

We demonstrate a significantly worse 5-year CSS and OS for men with GG2, fIR, and uIR PCa treated with AS compared to AT. Our analysis suggests that AS should not be the preferred treatment modality for IR PCa.

Multiparametric Magnetic Resonance Imaging Alone is Insufficient to Detect Grade Reclassification in Active Surveillance for Prostate Cancer

Multiparametric magnetic resonance imaging (mpMRI) has improved the detection of clinically significant prostate cancer. It remains unclear, however, whether mpMRI can safely replace confirmatory or surveillance biopsies in men with low-risk disease managed with active surveillance (AS). Overall, 166 men were upgraded at a median of 29 mo (interquartile range 13-54). The overall negative predictive value (NPV) of mpMRI was 79.5% and ranged from 74.4% to 84.6% for all AS biopsies up to the fourth surveillance biopsy. In men with prostate-specific antigen density ≥0.15 ng/ml/cm³, the overall NPV of mpMRI was 65.5% and ranged from 57.1% to 73.3% across serial mpMRI scans. These findings support the hypothesis that mpMRI is helpful but insufficient to rule out pathological reclassification, especially at confirmatory biopsy or in the presence of other risk factors. PATIENT SUMMARY: Multiparametric magnetic resonance imaging (mpMRI) alone misses a considerable percentage of clinically significant prostate cancers (Gleason grade group ≥2) in men on active surveillance for low-risk prostate cancer. We conclude that mpMRI alone cannot safely replace surveillance prostate biopsies, particularly at confirmatory biopsy or in the presence of other risk factors.

Cost-utility analysis of focal high-intensity focussed ultrasound vs active surveillance for low- to intermediate-risk prostate cancer using a Markov multi-state model

OBJECTIVES

To estimate the relative cost-effectiveness of focal high-intensity focussed ultrasound (F-HIFU) compared to active surveillance (AS) in patients with low- to intermediate-risk prostate cancer, in France.

PATIENTS AND METHODS

A Markov multi-state model was elaborated for this purpose. Our analyses were conducted from the French National Health Insurance perspective, with a time horizon of 10 years and a 4% discount rate for cost and effectiveness. A secondary analysis used a 30-year time horizon. Costs are presented in 2016 Euros (€), and effectiveness is expressed as quality-adjusted life years (QALYs). Model parameters' value (probabilities for transitions between health states, and cost and utility of health states) is supported by systematic literature reviews (PubMed) and random effect meta-analyses. The cost of F-HIFU in our model was the temporary tariff attributed by the French Ministry of Health to the overall treatment of prostate cancer by HIFU (€6047). Our model was analysed using Microsoft Excel 2010 (Microsoft Corp., Redmond, WA, USA). Uncertainty about the value of the model parameters was handled through probabilistic analyses.

RESULTS

The five health states of our model were as follows: initial state (AS or F-HIFU), radical prostatectomy, radiation therapy, metastasis, and death. Transition probabilities from the initial F-HIFU state relied on four articles eligible for our meta-analyses. All were non-comparative studies. Utilities relied on a single cohort in San Diego, CA, USA. For a fictive cohort of 1000 individuals followed for 10 years, F-HIFU would be €207 520 more costly and would yield 382 less QALYs than AS, which means that AS is cost-effective when compared to F-HIFU. For a threshold value varying from €0 to 100 000/QALY, the probability of AS being cost-effective compared to F-HIFU varied from 56.5% to 60%. This level of uncertainty was in the same range with a 30-year time horizon.

CONCLUSION

Given existing published data, our results suggest that AS is cost-effective compared to F-HIFU in patients with low- and intermediate-risk prostate cancer, but with high uncertainty. This uncertainty must be scaled down by continuing to supply the model with new published data and ideally through a randomised clinical trial that includes cost-effectiveness analyses.

Impact of bilateral biopsy-detected prostate cancer on an active surveillance population

BACKGROUND

To assess factors that can predict active surveillance (AS) failure on serial transrectal ultrasound guided biopsies in patients with low-risk prostate cancer.

METHODS

We evaluated the records of 144 consecutive patients enrolled in AS between 2007 and 2014 at a single academic institution. Low risk inclusion criteria included PSA < 10 ng/ml, cT1c or cT2a, Grade Group (GG) 1, < 3 positive cores, and < 50% tumor in a single core with the majority having a PSA density of < 0.15. AS reclassification was defined as progression to GG ≥2, 3 or more cores, or core tumor volume ≥ 50%. Univariate and multivariate Cox proportional hazards regression analysis was used to determine predictors of reclassification and a match-pair analysis performed on a control group of patients choosing surgery.

RESULTS

Inclusion criteria were met by 130 men with a median follow-up of 52 months. The reclassification or AS failure rate was 38.5%, with the majority 41/50 (82%) finding GG ≥ 2 cancer. Most patients had unilateral disease on diagnostic biopsy (94.6%), but 40.7% had bilateral cancer detected during follow-up. Men with bilateral detected tumor were more likely to ultimately fail AS than patients with unilateral tumors (HR 4.089; P < 0.0001) and failed earlier with a reclassification-free survival of 32 vs 119 months respectively. In a matched-pair analysis using a population of 211 concurrent patients that chose radical prostatectomy rather than AS, 76% of patients with unilateral cancer on biopsy had bilateral cancer on final pathology.

CONCLUSIONS

The finding of bilateral prostate cancer on biopsy is associated with earlier AS reclassification. Finding bilateral disease may not represent disease progression, but rather enhanced detection of more extensive disease highlighting the importance of confirmatory biopsy.

RETRACTED: Recommandations françaises du Comité de Cancérologie de l’AFU – Actualisation 2018–2020 : cancer de la prostate French ccAFU guidelines – Update 2018–2020: Prostate cancer

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). Cet article est retiré de la publication à la demande des auteurs car ils ont apporté des modifications significatives sur des points scientifiques après la publication de la première version des recommandations. Le nouvel article est disponible à cette adresse: DOI:10.1016/j.purol.2019.01.007. C’est cette nouvelle version qui doit être utilisée pour citer l’article. This article has been retracted at the request of the authors, as it is not based on the definitive version of the text because some scientific data has been corrected since the first issue was published. The replacement has been published at the DOI:10.1016/j.purol.2019.01.007. That newer version of the text should be used when citing the article.

[Active surveillance of prostate cancer]

Several prospective studies have demonstrated the safety of active surveillance as a first treatment of prostate cancer. It spares many patients of a useless treatment, with its potential sequelae. Patients with a low-risk cancer are all candidates for this approach, as recommended by the American Society of Clinical Oncology (ASCO). Some patients with an intermediate risk could be also concerned by active surveillance, but this is still being discussed. Currently, the presence of grade 4 lesions on biopsy is a contra-indication. Modalities included a repeated prostate specific antigen test and systematic rebiopsy during the first year after diagnosis. MRI is now proposed to better select patients at inclusion and also during surveillance. No life style changes or drugs are significantly associated with a longer duration of surveillance.

[CCAFU french national guidelines 2016-2018 on prostate cancer]

OBJECTIVES

The purpose of the guidelines national committee CCAFU was to propose updated french guidelines for localized and metastatic prostate cancer (PCa).

METHODS

A Medline search was achieved between 2013 and 2016, as regards diagnosis, options of treatment and follow-up of PCa, to evaluate different references with levels of evidence.

RESULTS

Epidemiology, classification, staging systems, diagnostic evaluation are reported. Disease management options are detailed. Recommandations are reported according to the different clinical situations. Active surveillance is a major option in low risk PCa. Radical prostatectomy remains a standard of care of localized PCa. The three-dimensional conformal radiotherapy is the technical standard. A dose of > 74Gy is recommended. Moderate hypofractionation provides short-term biochemical control comparable to conventional fractionation. In case of intermediate risk PCa, radiotherapy can be combined with short-term androgen deprivation therapy (ADT). In case of high risk disease, long-term ADT remains the standard of care. ADT is the backbone therapy of metastatic disease. In men with metastases at first presentation, upfront chemotherapy combined with ADT should be considered as a new standard. In case of metastatic castration-resistant PCa (mCRPC), new hormonal treatments and chemotherapy provide a better control of tumor progression and increase survival.

CONCLUSIONS

These updated french guidelines will contribute to increase the level of urological care for the diagnosis and treatment for prostate cancer. © 2016 Elsevier Masson SAS. All rights reserved.

Role of MRI in the Risk Assessment of Primary Prostate Cancer

A successful paradigm shift toward personalized management strategies for patients with prostate cancer (PCa) is heavily dependent on the availability of noninvasive diagnostic tools capable of accurately establishing the true extent of disease at the time of diagnosis and estimating the risk of subsequent disease progression and related mortality. Although there is still considerable scope for improvement in its diagnostic, predictive, and prognostic capabilities, multiparametric prostate magnetic resonance imaging (MRI) is currently regarded as the imaging modality of choice for local staging of PCa. A negative MRI, that is, the absence of any MRI-visible intraprostatic lesion, has a high negative predictive value for the presence of clinically significant PCa and can substantiate the consideration of active surveillance as a preferred initial management approach. MRI-derived quantitative and semi-quantitative parameters can be utilized to noninvasively characterize MRI-visible prostate lesions and identify those patients who are most likely to benefit from radical treatment, and differentiate them from patients with benign or indolent prostate pathology that may also be visible on MRI. This literature review summarizes current strategies how MRI can be used to determine a tailored management strategy for an individual patient.

Vitamin D3 Prevents Calcium-Induced Progression of Early-Stage Prostate Tumors by Counteracting TRPC6 and Calcium Sensing Receptor Upregulation

Active surveillance has emerged as an alternative to immediate treatment for men with low-risk prostate cancer. Accordingly, identification of environmental factors that facilitate progression to more aggressive stages is critical for disease prevention. Although calcium-enriched diets have been speculated to increase prostate cancer risk, their impact on early-stage tumors remains unexplored. In this study, we addressed this issue with a large interventional animal study. Mouse models of fully penetrant and slowly evolving prostate tumorigenesis showed that a high calcium diet dramatically accelerated the progression of prostate intraepithelial neoplasia, by promoting cell proliferation, micro-invasion, tissue inflammation, and expression of acknowledged prostate cancer markers. Strikingly, dietary vitamin D prevented these calcium-triggered tumorigenic effects. Expression profiling and in vitro mechanistic studies showed that stimulation of PC-3 cells with extracellular Ca²⁺ resulted in an increase in cell proliferation rate, store-operated calcium entry (SOCE) amplitude, cationic channel TRPC6, and calcium sensing receptor (CaSR) expression. Notably, administration of the active vitamin D metabolite calcitriol reversed all these effects. Silencing CaSR or TRPC6 expression in calcium-stimulated PC3 cells decreased cell proliferation and SOCE. Overall, our results demonstrate the protective effects of vitamin D supplementation in blocking the progression of early-stage prostate lesions induced by a calcium-rich diet. Cancer Res; 77(2); 355-65. ©2016 AACR.

The expanding landscape of diffusion-weighted MRI in prostate cancer

The added value of diffusion-weighted magnetic resonance imaging (DW-MRI) for the detection, localization, and staging of primary prostate cancer has been extensively reported in original studies and meta-analyses. More recently, DW-MRI and related techniques have been used to noninvasively assess prostate cancer aggressiveness and estimate its biological behavior. The present article aims to summarize the potential applications of DW-MRI for noninvasive optimization of pretherapeutic risk assessment, patient management decisions, and evaluation of treatment response.

[Active surveillance for prostate cancer]

Active surveillance is part of the therapeutic possibilities of localized prostate cancer at low-risk of progression. Patients are eligible for this support modality if they meet specific criteria of indolent cancer. In this population, active surveillance will consist of a regular physical examination, monitoring of PSA and repeating prostate biopsies and/or MRI to assess the absence of evolution of the diagnosed prostate cancer. In case of modification or worsening of the monitoring criteria in favor of evolution of the cancer, the patient will be offered a deferred active treatment such as radical prostatectomy, external beam radiotherapy, brachytherapy or focal treatment. For patients still meeting the eligibility criteria, active surveillance avoids an unnecessary treatment potentially responsible of genitourinary adverse events.